JP2017537302A - Pressure sensor including a deformable pressure channel - Google Patents

Abstract

Techniques for performing pressure sensing using a pressure sensor that includes a deformable pressure channel are described herein. A pressure channel is an object having a cross section that defines a void. The deformable pressure channel is based on the pressure difference between the cavity pressure in the cavity in which at least a portion of the pressure channel is suspended and the channel pressure in the pressure channel, such as bending deformation. , Shear deformation, elongation deformation, etc.) pressure channel having at least one curved portion. [Selection] Figure 5

Description

  [0001] The subject matter described herein relates to pressure sensors.

  [0002] Micromechanical devices are commonly used to make many types of sensors, including but not limited to pressure sensors, accelerometers, gyroscopes, and magnetometers. Over time, customers are constantly demanding to reduce the size, cost and power consumption of the above sensors by integrating the sensors into the combined sensors. However, different fabrication processes are often used to fabricate different types of sensors. Using different fabrication processes for each type of sensor makes integration difficult.

  [0003] Conventional micromechanical pressure sensors are typically formed in an electronic package having a membrane (also called a diaphragm) that extends to be coplanar with the substrate above the cavity in the substrate. To do. The relative change in pressure above the membrane relative to the pressure below the membrane creates a true force that deforms the membrane. Capacity-based principles are used to detect the magnitude of change so that larger capacity corresponds to a larger magnitude.

  [0004] For example, a strain sensor may be incorporated into a membrane. The strain sensor may include a piezoelectric material formed from a silicon substrate of a pressure sensor from which a membrane can be made. In another example, the electrode may be in a cavity and the capacity increases as the membrane moves closer to the electrode due to membrane deformation. According to this example, when a voltage is applied between the membrane and the electrode, the charge difference between the membrane and the electrode is related to their separation distance.

  [0005] In such conventional pressure sensors, the support for the membrane is attached to the surrounding electronic package. When an electronic package is attached to a circuit board, temperature and stress changes can be transferred into the support for the membrane, thereby providing an incorrect indication of the magnitude of the change. Moreover, it is well known that piezoelectric materials are relatively sensitive to temperature changes.

  [0006] Indications based on changes in temperature and stress if changes in temperature and stress are due to tensile forces within the sensor, eg, tensile forces resulting from differences in coefficient of thermal expansion (CTE) between the materials within the sensor Calibration techniques may be used to remove errors. For example, the reference sensing element may be used in combination with the primary sensing element to form a differential reading between the primary sensing element and the reference sensing element. However, using such a calibration technique may consume a significant amount of area on the substrate, increase the cost of the sensor, and / or may not adequately eliminate errors. Furthermore, it may not be possible to compensate for stress changes outside the sensor.

  [0007] Macroscopic pressure sensors are often based on a deformation of a Bourdon tube mechanically coupled to a dial gauge.

  [0008] Various approaches for implementing pressure sensor technology using a pressure sensor including a deformable pressure channel, among others, are described herein. A pressure channel is an object having a cross section that defines a void. A deformable pressure channel is based on a pressure difference between a cavity pressure in a cavity in which at least a portion of the pressure channel is suspended and a vessel pressure in the pressure channel, such as bending deformation, shear deformation, A pressure conduit having at least one curvilinear portion configured to deform (elongate, etc.).

  [0009] An exemplary pressure sensor is described that includes a semiconductor substrate, a pressure conduit, and a transducer. The semiconductor substrate includes a cavity. The pressure channel has a cross section that defines a void. The pressure passage has at least one curved portion configured to deform based on a pressure difference between the cavity pressure in the cavity and the passage pressure in the pressure passage. At least a first portion of the pressure channel is suspended within the cavity. A transducer is coupled to the first portion of the pressure conduit. The transducer has attributes that change with structural deformation of the pressure channel.

  [0010] An exemplary method is also described. In a first exemplary method, a semiconductor substrate including a cavity is provided. A pressure channel having a cross section defining a void is fabricated. The pressure passage has at least one curved portion configured to deform structurally based on a pressure difference between the cavity pressure within the cavity and the passage pressure within the pressure passage. At least a portion of the pressure channel is suspended within the cavity. A transducer is fabricated that is coupled to a portion of the pressure channel. The transducer has attributes that change with structural deformation of the pressure channel.

  [0011] In a second exemplary method, cavity pressure is received in a cavity included in a semiconductor substrate of the pressure sensor. The channel pressure is received in the pressure channel of the pressure sensor. The pressure channel has a cross section that defines a void. The pressure channel has at least one curved portion configured to deform structurally based on a pressure difference between the cavity pressure and the channel pressure. At least a portion of the pressure channel is suspended within the cavity. An attribute of a transducer coupled to a portion of the pressure channel is measured. The attributes change with the structural deformation of the pressure channel.

  [0012] An illustrative system is also described. The first exemplary system includes cavity logic (cavity logic), channel logic (channel logic), and transducer logic (transducer logic). The cavity logic is configured to provide a semiconductor substrate that includes a cavity. The conduit logic is configured to produce a pressure conduit having a cross section that defines a void. The pressure passage has at least one curved portion configured to deform structurally based on a pressure difference between the cavity pressure in the cavity and the passage pressure in the pressure passage. At least a portion of the pressure channel is suspended within the cavity. The transducer logic is configured to fabricate a transducer coupled to a portion of the pressure channel. The transducer has attributes that change with structural deformation of the pressure channel.

  [0013] A second exemplary system includes measurement logic. A cavity included in the semiconductor substrate of the pressure sensor receives the cavity pressure. The pressure channel of the pressure sensor receives the channel pressure. The pressure channel has a cross section that defines a void. The pressure conduit has at least one curved portion configured to structurally deform based on a pressure difference between the cavity pressure and the conduit pressure. At least a portion of the pressure channel is suspended within the cavity. The transducer is coupled to a portion of the pressure channel. Measurement logic measures transducer attributes that change with structural deformation of the pressure channel.

  [0014] An exemplary computer program product is also described. The computer program product includes a computer readable medium having recorded thereon computer program logic (computer program logic) for enabling a processor-based system to produce a pressure sensor. The computer program logic includes a first program logic module, a second program logic module, and a third program logic module. The first program logic module is for enabling a processor-based system to provide a semiconductor substrate including a cavity. The second program logic module is for enabling the processor-based system to produce a pressure channel having a cross section that defines a void. The pressure passage has at least one curved portion configured to deform structurally based on a pressure difference between the cavity pressure in the cavity and the passage pressure in the pressure passage. At least a portion of the pressure channel is suspended within the cavity. The third program logic module is for enabling a processor-based system to produce a transducer coupled to a portion of the pressure channel. The transducer has attributes that change with structural deformation of the pressure channel.

  [0015] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter. Moreover, it should be noted that the present invention is not limited to the specific examples described in the detailed description and / or other sections of this document. Such examples are presented herein for illustrative purposes only. Further embodiments will be apparent to those skilled in the art based on the teachings contained herein.

  [0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, exemplify the embodiments, explain the principles of the embodiments together with the description, and make and use the disclosed techniques by those skilled in the art. Further help to make it possible.

[0017] A cross-section of a wafer is shown to illustrate the fabrication of a pressure conduit according to embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure conduit according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure conduit according to the embodiments described herein. [0018] FIG. 4 is a top view of an exemplary deformable pressure conduit having a sickle shape according to embodiments described herein. [0019] FIG. 5 illustrates an exemplary pressure sensor including the deformable pressure conduit shown in FIG. 4 in accordance with embodiments described herein. [0020] FIG. 5 illustrates an exemplary pressure sensor including two sensing elements according to embodiments described herein. Fig. 4 illustrates an exemplary pressure sensor including two sensing elements according to embodiments described herein. [0021] FIG. 9 illustrates an exemplary pressure sensor having a respective binding arrangement according to embodiments described herein. Fig. 4 illustrates an exemplary pressure sensor having a respective coupling arrangement according to embodiments described herein. Fig. 4 illustrates an exemplary pressure sensor having a respective coupling arrangement according to embodiments described herein. [0022] FIG. 6 is a side view of a pressure sensor according to an embodiment described herein. [0023] FIG. 6 is a simplified top view of a multi-cavity pressure sensor according to embodiments described herein. [0024] A cross-section of a wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. A cross section of the wafer is shown to illustrate the fabrication of a pressure sensor according to the embodiments described herein. [0025] Fig. 4 represents a pressure conduit having an opening according to embodiments described herein. [0026] FIG. 6 depicts a flowchart of an exemplary method for fabricating a pressure sensor according to embodiments described herein. [0027] FIG. 2 is a block diagram of an exemplary fabrication system in accordance with embodiments described herein. [0028] FIG. 6 depicts a flowchart of an exemplary method for using a pressure sensor according to embodiments described herein. [0029] FIG. 4 is a block diagram of an exemplary measurement system according to embodiments described herein. [0030] FIG. 6 is a block diagram of a computing system that may be used to implement various embodiments.

[0031] The function and effect of the disclosed technology will become more apparent from the detailed description set forth below when considered in conjunction with the drawings, in which like reference characters identify corresponding elements throughout. . In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit in the corresponding reference number.
I. Introduction
[0032] The following detailed description refers to the accompanying drawings, which illustrate exemplary embodiments of the invention. However, the scope of the invention is not limited to these examples, but instead is defined by the appended claims. Accordingly, embodiments other than those illustrated in the accompanying drawings, for example, modified variations of the illustrated embodiments, may nevertheless be encompassed by the present invention.

[0033] References herein to “one embodiment”, “examples”, “exemplary examples”, etc., that illustrate the described embodiments may include specific functions, structures, or features. However, all embodiments may not necessarily include that particular function, structure, or feature. Moreover, such idioms do not necessarily refer to the same embodiment. Furthermore, when a particular function, structure, or feature is described in connection with an embodiment, it is known to those skilled in the art to implement such function, structure, or feature in connection with another embodiment. It is considered to be within range.
II. Illustrative example
[0034] The exemplary embodiments described herein can implement pressure sensor technology (eg, volume-based pressure sensor technology) using a pressure sensor that includes a deformable pressure channel. A pressure channel is an object having a cross section that defines a void. A deformable pressure channel is based on a pressure difference between a cavity pressure in a cavity in which at least a portion of the pressure channel is suspended and a pressure in the pressure channel, such as bending deformation, shearing. A pressure conduit having at least one curved portion configured to deform, e.g. deform).

  [0035] The pressure sensor may include a structure engraved from one piece of single crystal silicon. Engraving the structure from a single piece of single crystal silicon, for example, from a mechanical point of view, silicon contains relatively few defects (eg, is free of defects) and / or silicon is relatively well managed A benefit may be provided because it may be a material. Some pressure sensors described herein are capacitive based, meaning that they include one or more capacitors for measuring pressure differences. Insulation techniques may be used to fabricate capacitors having flat plates that are not shorted. For example, a trench isolation process may be utilized, in which the insulating section is embedded in the wafer before the structure is engraved so that the insulating section electrically insulates the pieces of the structure, but mechanically To join together. It will be appreciated that the isolation techniques referred to herein are not limited to use with capacitive-based pressure sensors. For example, the isolation technique may be used in any suitable type of pressure sensor (eg, a pressure sensor that is not capacitive based). A number of exemplary techniques for embedding an isolation section in a wafer are disclosed in US patent application entitled “Strengthened Micro-Electromechanical Devices and Methods of Making Theof”. 2012/0205752.

  [0036] The exemplary techniques described herein have various benefits compared to the prior art for pressure sensing. For example, exemplary techniques may be characterized by relatively low stress / temperature sensitivity. Thus, the exemplary technique may be less affected by outer package stress than conventional pressure sensing techniques. For example, the exemplary pressure sensor described herein has a support configured to physically support a pressure channel that prevents external tensile forces from being transmitted to the sensing area of the pressure sensor. May be. The sensing area of the pressure sensor is defined by a cavity in the semiconductor substrate. Accordingly, the exemplary technique may be able to couple the outer pressure change inside the pressure sensor while preventing the temperature-induced outer package stress from being coupled inside the pressure sensor.

  [0037] For example, the distance between the point where the pressure conduit connects to the substrate and the point where the pressure conduit connects to the transducer may be relatively small. In another example, the distance between the point where the transducer connects to the substrate and the point where the transducer connects to the pressure channel may be relatively small. In yet another example, the distance between the point where the pressure conduit connects to the substrate and the point where the transducer connects to the substrate may be relatively small. Making a pressure sensor characterized by any one or more of the above relatively small distances has a relatively low probability that package stress will enter the pressure sensor compared to a conventional pressure sensor. obtain. For example, any one or more of the above distances may be no more than one third of the length of the smaller side of the surrounding rectangle, where the rectangle is at least a portion of the pressure channel. A rectangle with a minimum area (in the plane of the wafer on which the pressure sensor is fabricated) surrounding the cavity suspended therein. The described pressure sensor may not react to temperature changes. The described pressure sensor may be characterized by a relatively high signal-to-noise ratio (SNR) compared to conventional pressure sensors.

  [0038] The exemplary pressure sensor described herein may be characterized by a relatively low manufacturing cost. For example, the described pressure sensor may be fabricated based on current fabrication techniques. The pressure sensor described may be capable of being fabricated using a fabrication process that is similar to or the same as the process used to fabricate inertial sensors, such as accelerometers and / or gyroscopes. For example, building a pressure sensor on the same wafer as such an accelerometer and / or gyroscope (eg, simultaneously) may reduce the cost of the pressure sensor. The pressure sensor may share a common sensing principle (eg, variable capacitance based motion sensing) with the accelerometer and / or gyroscope. Thus, because pressure sensors, accelerometers and / or gyroscopes share circuitry, making them on the same wafer only adds to the relatively small cost of the wafer or device fabricated on it. There is.

  [0039] FIGS. 1-3 illustrate wafer cross-sections 100, 200, and 300 to illustrate the fabrication of a pressure conduit according to the embodiments described herein. Fabrication is in the process used to construct micromechanical devices as described in US Pat. No. 6,239,473, entitled “Trench Isolation for Micromechanical Devices”. Although the scope may be based on, the scope of the exemplary embodiment is not limited thereto. A portion of the process described in US Pat. No. 6,239,473 is represented in FIGS.

  [0040] A trench 104 is formed in the wafer 102 as shown in FIG. It should be noted that the wafers discussed herein may be referred to as silicon wafers for purposes of illustration, but are not intended to be limiting. It will be appreciated that each wafer (eg, wafer 102) may include any suitable type of material such as, but not limited to, silicon, gallium arsenide, and the like. The trench 104 may be formed by deep reactive ion etching using a high etch rate, high selectivity etch, although the scope of the exemplary embodiment is not limited thereto. The trench 104 may be etched in a high density plasma using, for example, a SF6 gas mixture. One technique for etching trenches in a high density plasma using SF6 gas mixture is described in US Pat. No. 5,501,893 entitled “Method of Anisotropically Etching Silicon”. ing.

  [0041] The trench 104 may have various widths at points along the axis 115 that are perpendicular to the top surface 116 of the wafer 102 in the cross-section of the trench 104. The etch used to form the trench 104 is controlled so that the profile of the trench 104 is bent or tapered by the opening 106 of the trench 104 having a width W1 that is narrower than the width W2 of the bottom 108 of the trench 104. Can be done. Such a taper can increase the accuracy with which electrical insulation is achieved in subsequent processing. The taper profile may be achieved in reactive ion etching by adjusting the degree of passivation or by changing the parameters of the discharge during etching (eg, power, gas flow and / or pressure). Since the trench 104 can be at least partially filled with a dielectric, the width W1 of the opening 106 may be selected to be relatively small (eg, less than 2 microns (μm)). The depth D of the trench 104 may be in the range of 10 to 50 μm. The width W2 of the bottom 108 of the trench 104 may be in the range of 2 to 3 μm. The above exemplary width and depth measurements are provided for purposes of illustration and are not intended to be limiting. It will be appreciated that any suitable width and depth values may be used.

[0042] The maximum width _WTR of the trench 104 is defined as the width of the trench 104 at a point along the axis 115, which is smaller than the width of the trench 104 at any other point along the axis 115. Absent. Although the maximum width _WTR of the trench 104 may be generally smaller than the depth D of the trench 104, the scope of the exemplary embodiment is not limited thereto. The aspect ratio of the trench 104 is defined as D / W _TR (ie, the depth of the trench 104 divided by the maximum width of the trench 104). The aspect ratio can be any suitable value (eg, greater than 3 (greater than 3), greater than 3.5 (greater than 3.5), greater than 4 (greater than 4), greater than 5 (greater than 5). Etc.). For example, the trench 104 is configured to have an aspect ratio greater than 4 (greater than 4) to improve the manufacturability and / or pressure sensing performance of the exemplary pressure sensor described herein. .

  [0043] Etching the trench 104 includes alternating the etching step (mixture of SF6 and argon) with the passivation step (freon with argon) in an inductively coupled plasma (ICP). Etch rates greater than 2 μm / min may be achieved with high selectivity to (> 50: 1) and oxide (> 100: 1). The power and duration of the etch cycle may be increased as trench 104 is deepened to achieve a tapering profile. Although the trench 104 geometry is shown to be inwardly curved, any trench profile may be accommodated by adjustments in the microstructure process. Sufficient insulation results may be achieved by any of a variety of known trench etch chemistries.

  [0044] As shown in FIG. 2, the wafer 102 is oxidized. By oxidizing the wafer 102, a silicon dioxide layer 210 (or another suitable insulating dielectric material) is provided on the top surface 116 of the wafer 102 and along the sidewalls 218 and bottom 108 of the trench 104. For example, the silicon dioxide layer 210 may form a silicon dioxide lining along the sidewall 218 and bottom 108 of the trench 104. The thickness of the silicon dioxide layer 210 may exceed 1 μm, for example. Formation of the silicon dioxide layer 210 may be accomplished using chemical vapor deposition (CVD) techniques or by an oxidation reaction of silicon at a relatively high temperature. In thermal oxidation, the wafer 102 may be exposed to an oxygen rich environment at a temperature in the range of 900-1150 ° C. In this example, the oxidation process consumes a silicon surface to form silicon dioxide layer 210. It will be appreciated that the wafer may be formed from any suitable type of semiconductor material and its surface may be consumed to form an oxide layer other than silicon dioxide. The volume expansion resulting from this process causes the sidewalls 218 of the trenches 104 to violate each other and the silicon dioxide layer 210 seals at the location 214 thereby closing the opening 106.

  [0045] Since the width W1 of the opening 106 of the trench 104 is narrower than the width W2 of the bottom 108 of the trench 104, the air gap 212 is formed. Although the air gap 212 may not normally be desirable in manufacturing, in the embodiment described herein, the air gap 212 is used as a basis for the pressure sensor design.

[0046] The air gap 212 may have various widths at each point along the axis 215, the axis being perpendicular to the top surface 116 of the wafer 102 in the cross section of the air gap 212. The maximum width W _MAX of the air gap 212 is defined as the width of the air gap 212 at a point along the axis 215 that is not less than the width of the air gap 212 at any other point along the axis 215. . The air gap 212 may be formed to have a maximum width that is less than a specified distance. For example, the void may be formed to have a maximum width that is less than 2 μm, less than 1 μm, less than 0.3 μm, or any other suitable distance.

  [0047] In an exemplary embodiment, oxidizing the wafer 102 includes first and second oxide walls 217a and 217b on both sides of the shaft 215, thereby forming the first and second oxide walls 217a and 217b. A gap 212 is defined between the oxide wall 217b and the oxide wall 217b.

  [0048] As shown in FIG. 3, a pressure channel 320 is provided by releasing the silicon dioxide layer 210 from contact with the wafer 102 by subsequent patterning and release steps. The difference between the pressure in the air gap 212 and the pressure in the surrounding region 322 causes the pressure passage 320 to undergo structural deformation (eg, bending deformation, shear deformation, elongation deformation, etc.). It will be appreciated that such differences can change the shape of the void 212, but the scope of the exemplary embodiment is not limited thereto.

  [0049] The degree to which the pressure passage 320 is deformed is proportional to the maximum width of the gap 212, while the stiffness of the pressure passage 320 increases with the cube of the maximum width of the gap 212. Accordingly, it can be intuitively understood that utilizing a pressure channel 320 having a cross section defining a void having a relatively small dimension can provide a desirable pressure sensing function. For example, a relatively larger structure (eg, many conventional pressure sensor diaphragms) can be expected to provide greater compliance (ie, less stiffness) compared to a relatively smaller structure. However, the size scale of the pressure sensor 320 may be small enough so that the increase that occurs with respect to the compliance of the pressure sensor 320 can exceed the decrease that occurs with respect to deformation of the pressure sensor 320. The pressure conduit 320 may be configured to have a height H1 of less than 50 μm, less than 40 μm, less than 30 μm, less than 20 μm, or any other suitable height. The void 212 may be configured to have a height H2 of less than 30 μm, less than 20 μm, less than 10 μm, less than 5 μm, or any other suitable height.

  [0050] FIG. 4 is a top view of an exemplary deformable pressure conduit 420 having a sickle shape, in accordance with embodiments described herein. Pressure passage tube 420 is shown suspended within cavity 486 etched from wafer 458. Pressure passage tube 420 is supported by cavity 486 at location 407. The cross section of the pressure channel 420 may be defined in the plane 403. It will be appreciated that the cross section defined by plane 403 may be represented as cross section 300 shown in FIG. In the example of FIG. 4, the pressure conduit 420 has an undeformed shape 401 when the conduit pressure in the pressure conduit 420 is equal to the cavity pressure in the cavity 486. When the channel pressure becomes greater than the cavity pressure, the pressure channel 420 is structurally deformed (as represented by the arrow 405) so that the pressure channel 420 has a deformed shape 402. The pressure outside the cavity 486 sets the channel pressure in the pressure channel 420 at the channel pressure inlet / outlet 404.

  [0051] The channel pressure inlet / outlet 404 is an opening in the pressure channel 420 that exposes the channel pressure of the pressure channel 420 to an environment outside the pressure channel 420. A pressure inlet / outlet is an opening that exposes one or more environments to one or more other environments. Therefore, the passage pressure inlet / outlet 404 constitutes a pressure inlet / outlet. A vessel pressure entry / exit is an opening in a pressure vessel that exposes one or more environments to one or more other environments. Accordingly, the conduit pressure inlet / outlet 404 also constitutes a conduit pressure / inlet.

  [0052] Pressure passage tube 420 is shown as having a sickle shape for purposes of illustration, but is not intended to be limiting. It will be appreciated that the pressure conduit 420 can have any suitable shape. For example, the pressure conduit may include a serpentine shape, a spiral shape, a semi-circular shape, a plurality of concentric semi-circular portions each having a semi-circular shape, a linear shape that can be extended, or any combination thereof.

  [0053] FIG. 5 illustrates a pressure sensor 500 that includes a deformable pressure channel 520 according to embodiments described herein. As shown in FIG. 5, the pressure sensor 500 further includes a transducer 503 that is mechanically coupled to the pressure sensor 520 by an intervening structural element 502 (also known as a mechanical coupling). Pressure passage tube 520, transducer 503, and intervening structural element 502 (or at least a portion thereof) are suspended in cavity 586 etched from wafer 558. The pressure channel 520 is supported by the semiconductor substrate 580 of the wafer 558 at point 507. As shown in FIG. 5, the transducer 503 is a silicon structure etched primarily from the wafer 558. The transducer 503 includes a first set of capacitor plates 511a-511j, a second set of capacitor plates 512a-512j, and a third set of capacitor plates 509a-509k. The capacitor plates 511a and 512a are between the capacitor plates 509a and 509b, the capacitor plates 511b and 512b are between the capacitor plates 509b and 509c, and the capacitor plates 511c and 512c are the capacitor electrodes. And so on, between plates 509c and 509d. The capacitor plate 511a is between the capacitor plate 509a and the capacitor plate 512a, the capacitor plate 511b is between the capacitor plate 509b and the capacitor plate 512b, and so on. The capacitor plate 512a is between the capacitor plate 511a and the capacitor plate 509b, the capacitor plate 512b is between the capacitor plate 511b and 509c, and so on.

  [0054] Capacitor plates 511a-511j in the first set are electrically coupled using electrical traces 513 and vias 523. For example, via 523 electrically couples electrical trace 513 to each capacitor plate 511a-511j. The capacitor plates 512a-512j in the second set are electrically coupled. For example, via 524 electrically couples electrical trace 514 to each capacitor plate 512a-512j. The capacitor plates 509a-509k in the third set are electrically coupled.

  [0055] The first set of capacitor plates 511a-511j is electrically isolated from the second set of capacitor plates 512a-512j and the third set of capacitor plates 509a-509k. For example, the insulation section 519 insulates the first set of capacitor plates 511a-511j from the second set of capacitor plates 512a-512j, and the insulation section 515a includes the first set of capacitor plates 511a-511j. Are isolated from the third set of capacitor plates 509a-590k. The second set of capacitor plates 512a-512j is also electrically isolated from the third set of capacitor plates 509a-509k. For example, the isolation section 515b insulates the second set of capacitor plates 512a-512j from the third set of capacitor plates 509a-509k. Thus, utilizing an insulation section (eg, insulation sections 515a-515b and 519) may allow various regions of the transducer 503 to be mechanically connected but electrically isolated. I understand.

  [0056] The first capacitance is provided based on the proximity of the capacitor plates 511a-511j in the first set to the respective capacitor plates 509a-509j in the third set. The second capacitance is provided based on the proximity of the capacitor plates 512a-512j in the second set to the respective capacitor plates 509b-509k in the third set. The capacitor plates 509a-509j in the third set may be referred to as the first subset of the third set, and the capacitor plates 509b-509k in the third set are the second set of the second set. It may be called a subset. Each of the first subset and the second subset may be referred to as a set for itself. The capacitor plates 511a to 511j in the first set have the capacitor plates 509a to 509a in the third set even if the capacitor plates 512a to 512j in the second set are alternately arranged with the capacitor plates 509a to 509k. Note that 509k is considered interleaved. Similarly, the capacitor plates 512a to 512j in the second set are the capacitor electrodes in the third set even if the capacitor plates 511a to 511j in the first set are also alternately arranged with the capacitor plates 509a to 509k. It is considered that the plates 509a to 509k are arranged alternately.

  [0057] When the pressure difference between the pressure in the pressure passage 520 and the pressure in the cavity 586 changes, the pressure passage 520 undergoes structural deformation. When the pressure channel 520 is deformed, the structural deformation of the pressure channel 520 is coupled to the transducer 503 via the intervening structural element 502, so that the first set of capacitor plates 511 a-, as indicated by arrow 521. 511j and the second set of capacitor plates 512a-512j are moved relative to the third set of capacitor plates 509a-509k. For example, the springs 525a and 525b indicate that the first set of capacitor plates 511a-511j and the second set of capacitor plates 512a-512j move relative to the third set of capacitor plates 509a-509k. to enable. Springs 525a and 525b are relatively flexible compared to another portion of transducer 503. Note that the serpentine flexible leads 517 a and 517 b are also relatively flexible compared to another portion of the transducer 503. Meandering flexible leads 517a and 517b are discussed in further detail below.

  [0058] The movement of the first set of capacitor plates 511a-511j and the second set of capacitor plates 512a-512j in the direction of arrow 521 (ie, left in FIG. 5) is the same as that of capacitor plates 511a-511j. The distance between each capacitor plate 509a-590j is decreased, thereby increasing the first capacitance (i.e., the capacitance between capacitor plate 511a-511j and each capacitor plate 509a-590j). . The aforementioned movement also increases the distance between the capacitor plates 512a-512j and the respective capacitor plates 509b-590k, thereby providing a second capacitance (ie, the capacitor plates 512a-512j and the respective capacitors). The capacity between the electrode plates 509b to 590k) is reduced. Therefore, in the embodiment of FIG. 5, the change in the first capacitance is opposite to the change in the second capacitance.

  [0059] Serpentine flexible leads 517a and 517b provide respective flexible mechanical connections between transducer 503 and semiconductor substrate 580. For example, the use of serpentine flexible leads 517a and 517b allows the package stress to be a third set of capacitor plates 509a--a first set of capacitor plates 511a-511j and a second set of capacitor plates 512a-512j. It can prevent affecting the operation for 509k. The serpentine flexible lead 517a electrically couples electrical characteristics (eg, charge) associated with the first set of capacitor plates 511a-511j to the first trace 516a. The serpentine flexible lead 517b electrically couples electrical characteristics (eg, charge) associated with the second set of capacitor plates 512a-512j to the second trace 516b. Electrical characteristics (eg, charge) associated with the third set of capacitor plates 509a-509k are electrically coupled to the third trace 516c.

  [0060] A measurement circuit (eg, an electrical circuit) is electrically coupled to the first trace 516a, the second trace 516b, and / or the third trace 516c to thereby cause the passage pressure in the pressure passage 520 to be reduced. And a non-equilibrium termination or differential capacitance measurement representing the pressure difference between the cavity pressure in the cavity 586 may be performed. It will be appreciated that any of a variety of well-known volumetric techniques may be used to provide a non-equilibrium termination indication or differential indication for pressure differential. In one example, a combination of multiple (eg, two) unbalanced termination capacitance measurements may be used to provide a differential capacitance measurement. According to this example, the combination may be a sum to obtain a measure of pressure difference, and the combination may be a subtraction to obtain a measure of acceleration. It will be appreciated that changing the path selection of traces 516a-516c changes whether the difference or sum is used to obtain the pressure difference measure or acceleration measure described above. Differential capacitance measurements are discussed in more detail below, primarily with respect to FIG.

  [0061] The transducer 503 limits the extent to which the first set of capacitor plates 511a-511j and the second set of capacitor plates 512a-512j move relative to the third set of capacitor plates 509a-509k. Is shown to include a bump stop 526 configured as such. Traces 527a and 527b are provided on the bump stop 526. Trace 527a has the same potential (ie, voltage) as the second set of capacitor plates 512a-512j and second trace 516b. Trace 527b has the same potential as the first set of capacitor plates 511a-511j and first trace 516a. A single bump stop 526 is shown in FIG. 5 for purposes of illustration, but is not intended to be limiting. It will be appreciated that the transducer 503 may include any suitable number of bump stops (eg, none, two, three, etc.).

  [0062] Transducer 503 is represented for purposes of illustration as the deformable capacitor structure of FIG. 5, but is not intended to be limiting. The transducer 503 may be any suitable type of transducer. For example, those skilled in the art will recognize that the transducer 503 may include structures that use piezoelectric and / or piezoresistive techniques to convert the movement of the pressure channel 520 into an electrical signal. For example, the transducer 503 is configured to generate a charge (eg, electrical charge) based on a force (eg, mechanical stress) acting on the piezoelectric element (piezoelectric element) as a result of structural deformation of the pressure channel 520. A piezoelectric element may also be included. According to this example, the force may cause distortion of the piezoelectric element that causes the piezoelectric element to generate a charge. In another example, the transducer 503 may include a piezoresistive element having a resistance (eg, electrical resistance) that changes based on a force (eg, mechanical stress) acting on the piezoresistive element as a result of deformation of the pressure conduit 520. Good. According to this example, the force may cause distortion of the piezoresistive element that changes the resistance of the piezoresistive element. Furthermore, optical and / or magnetic techniques may be used to sense the operation of the pressure channel 520. It will be appreciated that the transducer 503 may be fabricated in any of a variety of ways, for example with or without an isolation section 515. It will further be appreciated that the transducer 503 may be fabricated using a silicon on insulator (SOI) wafer or epitaxial silicon.

  [0063] In the exemplary embodiment, transducer 503 and deformable pressure channel 520 are formed using the same process. For example, the process may include any suitable number of etching steps and / or any suitable number of lithography steps. In one aspect of this embodiment, an etching step may be used to form the transducer 503 and the deformable pressure channel 520. In another aspect, a first etching step may be used to form the transducer 503 and a second etching step that is different from the first etching step is used to form the pressure channel 520. May be. In accordance with this aspect, the first etching step may configure (eg, optimize) the geometry of transducer 503 for the intended function of transducer 503, and the second etching step may include pressure channel 520. The geometry of the pressure channel 520 may be configured (eg, optimized) for the intended function.

The geometry of transducer 503 or pressure conduit 520 may include the shape of the dielectric therein, the thickness of the dielectric therein, etc., or any combination thereof. For example, the geometry of the pressure channel 520 can be the maximum width of the trench in which the pressure channel 520 is formed, the depth of the trench in which the pressure channel 520 is formed, the dielectric in which the pressure channel 520 is formed. It may include the maximum width of the void formed by the body, the depth of the void formed by the dielectric in which the pressure channel 520 is formed, or the like.

  [0064] In yet another aspect of this embodiment, the same lithography step may be used to form transducer 503 and deformable pressure conduit 520. In yet another aspect, a first lithography step may be used to form the transducer 503 and a second lithography step different from the first lithography step is used to form the pressure channel 520. May be. According to this aspect, the first lithography step may configure (eg, optimize) the geometry of the transducer 503 for the intended function of the transducer 503, and the second lithography step may include the pressure path. For the intended function of the tube 520, the geometry of the pressure channel 520 may be configured (eg, optimized).

  [0065] In another exemplary embodiment, the transducer 503 and the deformable pressure channel 520 share the same dielectric. In yet another exemplary embodiment, the dielectric used to form the transducer 503 is different from the dielectric used to form the deformable pressure channel 520.

  [0066] In FIG. 5, the location 507 is the location (also known as the point) where the pressure conduit 520 couples to the semiconductor substrate 580. Location 528 is where the pressure channel 520 is coupled to the transducer 503. Location 529 is where the transducer 503 is coupled to the semiconductor substrate 580. Reducing (eg, minimizing) the distance between location 507 and location 528, the distance between location 507 and location 529, and / or the distance between location 528 and location 529 may result in package stress. May result in a relatively low probability of entering the pressure sensor 500. In addition, reducing such a distance is a natural thermal expansion between the material used to fabricate the pressure channel 520 (eg, silicon dioxide) and the material used to fabricate the transducer 503 (eg, silicon). Coefficient (CTE) mismatch may be reduced (eg, minimized).

  [0067] Some guidelines for determining the likelihood of package stress entering the pressure sensor 500 include any one or more of the aforementioned distances, at least one side of a rectangle surrounding the cavity 586. May be established by comparing with the length of. For example, in the exemplary embodiment, pressure sensor 500 is characterized by a surrounding rectangle defined by a length A along the X axis and a length B along the Y axis. The surrounding rectangle is defined as a rectangle having a minimum area that encloses a cavity in the plane of the wafer on which the pressure sensor is fabricated. Thus, the surrounding rectangle has a first parallel side and a second parallel side that is perpendicular to the first parallel side. Each of the first parallel sides has a first length. Each of the second parallel sides has a second length that is less than or equal to the first length.

  [0068] The plane defined by the X and Y axes in FIG. 5 represents the plane of the wafer 558 on which the pressure sensor 500 is fabricated. As shown in FIG. 5, the rectangle with the smallest area surrounding the cavity 586 in the plane of the wafer 558 has a first parallel side of length A along the X axis and a second of length B along the Y axis. Of parallel sides. Thus, the surrounding rectangle associated with pressure sensor 500 has an area equal to the product of A and B (ie, A times B).

  [0069] In one aspect of this embodiment, the distance between location 507 and location 529 may be 1/3 or less of length B. In another aspect, the distance between the location 507 and the location 528 may be 1/3 or less of the length B. In yet another aspect, the distance between location 528 and location 529 may be 1/3 or less of length B.

  [0070] Each of the traces 513, 514, 516a-516c, and 527a-527b may include a metal coating having a depth of approximately 350 nanometers (nm) and a width of approximately 2 μm, although The range is not limited to this. It will be appreciated that each of the traces 513, 514, 516a-516c and 527a-527b may include a metal coating having any suitable depth and width. The cavity 586 may have a depth B of approximately 1 millimeter (mm) and a width A of approximately 2 mm, although the scope of the exemplary embodiment is not limited thereto. It will be appreciated that the cavity 586 may have any suitable depth and width.

  [0071] FIG. 6 illustrates an exemplary pressure sensor 600 that includes two sensing elements 688a and 688b, according to the embodiments described herein. As shown in FIG. 6, the pressure sensor 688a includes a pressure channel 620a and a corresponding transducer 603a, which are mechanically coupled by an intervening structural element 602a. The pressure sensor 688b includes a pressure channel 620b and a corresponding transducer 603b, which are mechanically coupled by an intervening structural element 602b. Pressure channel tubes 620a and 620b, transducers 603a and 603b, and intervening structural elements 602a and 602b (or at least a portion thereof) are suspended in a cavity 686 etched from semiconductor substrate 680. For illustrative purposes, pressure passage tube 620a is shown surrounding at least a portion of transducer 603a and pressure passage tube 620b is shown surrounding at least a portion of transducer 603b. Pressure passage tube 620a is supported by semiconductor substrate 680 at location 607a, and pressure passage tube 620b is supported by semiconductor substrate 680 at location 607b.

  [0072] Although the sensing element 688a is shown in FIG. 6 to be a mirror image of the sensing element 688b for purposes of illustration, the scope of the exemplary embodiment is not so limited. For example, such symmetry may reduce the sensitivity of the pressure sensor 600 to the effects of acceleration. In the exemplary embodiment, pressure sensor 600 is configured such that the passage pressure in each of pressure passages 620a and 620b is approximately equal. According to this embodiment, as the pressure in the pressure passages 620a and 620b increases to be greater than the cavity pressure in the cavity 686, the pressure passages 620a and 620b move toward each other (eg, along the X axis). Deform. In further accordance with this embodiment, transducers 603a and 603b are configured such that, with deformation, the capacitance associated with transducer 603a increases and the capacitance associated with transducer 603b decreases, and vice versa. By considering the difference between the capacities, the pressure difference between the vessel pressure and the cavity pressure may be determined. By considering the total capacitance, the acceleration of the pressure sensor 600 along the X axis may be determined. For example, each of the transducers 603a and 603b includes accelerometer elements (ie, springs, masses, and transducers that convert mass motion into, for example, electrical signals).

  [0073] FIG. 7 illustrates another exemplary pressure sensor 700 that includes two sensing elements 788a and 788b, according to embodiments described herein. As shown in FIG. 7, pressure sensor 788a includes a pressure channel 720a and a corresponding transducer 703a, which are mechanically coupled by an intervening structural element 702a. The pressure sensor 788b includes a pressure channel 720b and a corresponding transducer 703b, which are mechanically coupled by an intervening structural element 702b. Pressure channel tubes 720a and 720b, transducers 703a and 703b, and intervening structural elements 702a and 702b (or at least a portion thereof) are suspended in a cavity 786 etched from semiconductor substrate 780. Each of the transducers 703a and 703b is shown to include two concentric semicircular portions for purposes of illustration, but is not intended to be limiting. Each of the semicircular portions has a semicircular shape. It will be appreciated that each of the transducers 703a and 703b may include any suitable number of semicircular portions (eg, one, two, three, four, etc.). Moreover, each of the transducers 703a and 703b may have a shape other than one or more semicircular portions.

  [0074] Although the sensing element 788a is shown in FIG. 7 as a mirror image of the sensing element 788b for purposes of illustration, the scope of the exemplary embodiment is not so limited. In the exemplary embodiment, pressure sensor 700 is configured such that the passage pressure in each of pressure passages 720a and 720b is approximately equal. According to this embodiment, when the pressure in the pressure passages 720a and 720b increases to be greater than the cavity pressure in the cavity 786, the pressure passages 720a and 720b move toward each other (eg, in the X axis). Along). In further accordance with this embodiment, transducers 703a and 703b are configured such that, with deformation, the capacitance associated with transducer 703a increases and the capacitance associated with transducer 703b decreases, and vice versa. By considering the difference between the capacities, the pressure difference between the vessel pressure and the cavity pressure may be determined. By considering the total capacitance, the acceleration of the pressure sensor 700 along the X axis may be determined.

  [0075] In FIG. 5, one pressure passage tube 520 is shown suspended within the cavity 586 for non-limiting illustration. In FIG. 6, two pressure passage tubes 620a and 620b are shown suspended within cavity 686 for non-limiting illustration. In FIG. 7, two pressure passage tubes 720a and 720b are shown suspended within cavity 786 for non-limiting illustration. It will be appreciated that any suitable number of pressure conduits may be suspended within each of the cavities 586, 686, and 786.

  [0076] In some exemplary embodiments, a lid covers the cavities 586, 686, 786. The lid may be any suitable material, such as another wafer or part thereof. For example, the wafer or portion thereof forming the lid may be electrically isolated from other conductive elements in each pressure sensor 500, 600, 700 by an insulating layer. In one exemplary embodiment, the lid seals the cavities 586, 686, 786 in a vacuum to provide a specified pressure within the cavities 586, 686, 786. For example, the specified pressure may be approximately 0 atmosphere. According to this example, the specified pressure may be in a range of 0.0 to 0.01 atmosphere, 0.0 to 0.05 atmosphere, 0.0 to 0.1 atmosphere, and the like. For example, when the specified pressure is approximately 0 atmosphere, the pressure sensors 500, 600, and 700 may not respond to temperature changes. In another exemplary embodiment, the lid seals the cavities 586, 686, 786 to provide a specified pressure of approximately 1 atmosphere. For example, the specified pressure may be in the range of 0.99 to 1.01 atmosphere, 0.95 to 1.05 atmosphere, 0.9 to 1.1 atmosphere, and the like.

  [0077] The specified pressure may be determined when the lid is installed in the pressure conduit 500, 600, or 700. It will be appreciated that lid bonding may be performed at relatively high temperatures. Thus, during cooling, the value of the specified pressure may decrease from the value at the time when the lid was installed on the pressure conduit 500, 600, 700 according to the pressure versus temperature relationship. It will also be appreciated that if the lid seals the cavities 586, 686, 786 in a vacuum, the specified pressure does not change during cooling.

  [0078] FIGS. 8a-8c illustrate exemplary pressure sensors 830, 860, and 890 having respective coupling arrangements, according to the embodiments described herein. As shown in FIG. 8 a, the pressure sensor 830 includes a pressure channel 820 suspended within a cavity 886. Pressure passage tube 820 is mechanically coupled to transducer 803 by intervening structural element 802a. The intervening structural element 802a has a “V” shape. When the channel pressure in the pressure channel 820 is greater than the cavity pressure in the cavity 886, the pressure channel deforms and expands in the positive Y direction. Expansion of the pressure channel 820 in the positive Y direction causes a force to act on the intervening structural element 802a at the connection point 829a. The action of force at the connection point 829a compresses (eg, folds) the intervening structural element 802a, as represented by arrow 831. The compression of the intervening structural element 802a causes a force to act on the transducer 803 in the negative X direction at the connection point 829b.

[0079] The work input into the intervening structural element 802a is equal to the work output from the intervening structural element 802a. Therefore, Win = Fin ^* din = Wout = Fout ^* dout, where Win is the input work, Wout is the output work, and Fin acts on the pressure channel 820 at the connection point 829a. Din is the distance that the connection point 829a moves in the positive Y direction, Fout is the force acting on the intervening structural element 802a at the connection point 829b, and dout is the negative X at the connection point 829b. The distance to move in the direction. In the exemplary embodiment, the stiffness of pressure passage tube 820 and the stiffness of transducer 803 are set such that dout is greater than din. According to this embodiment, a relatively small movement of the connection point 829a results in a relatively large movement of the connection point 829b, whereby the intervening structural element 802a functions as an operational amplifier. In another exemplary embodiment, the stiffness of the pressure channel 820 and the stiffness of the transducer 803 are set to make dot less than din. According to this embodiment, the relatively large movement of the connection point 829a results in a relatively small movement of the connection point 829b, so that the intervening structural element 802a functions as a motion attenuator.

  [0080] The intervening structural element 802b is described as responding to movement in the first direction by causing another movement in the second direction, and for purposes of illustration, the second direction is in the first direction. Although it is said to be vertical, it is not intended to be limited thereto. The intervening structural element (eg, the intervening structural element 802b) amplifies the first operation even if it is amplified in the specific direction by causing the second operation, which is an amplified version of the first operation, to occur in the specific direction. It will be appreciated that this is not necessary.

  [0081] As shown in FIG. 8b, the pressure sensor 860 includes a pressure channel 820, which is mechanically coupled to the transducer 803 by an intervening structural element 802b. The intervening structural element 802b is configured to be relatively hard in the X direction and relatively flexible in the Y direction. Accordingly, the intervening structural element 802b has anisotropic stiffness (ie, different stiffness in at least two orthogonal directions) and couples the pressure channel 820 to the transducer 803 anisotropically. Configuring the intervening structural element 802b to be flexible in a specified direction (eg, the Y direction in this example) is used to fabricate the material used to fabricate the pressure channel 820 and the transducer 803. It may prevent (reduce) package stress problems and / or effects from thermal expansion coefficient (CTE) mismatch with the material being made.

  [0082] The stiffness of the intervening structural element (eg, intervening structural element 802b) in the specified direction may be reduced for any of a variety of reasons. For example, if an intervening structural element is pushed in a specified direction and it is not desirable for the intervening structural element to respond in that direction, the stiffness of the intervening structural element in that direction may be reduced. In another example, if a relatively large distance exists between two points, the stiffness of the intervening structural element along the axis defined by those points may be reduced. In yet another example, if the thermal effect causes deformation of the pressure channel in a particular direction where response is not desired, the stiffness of the intervening structural element in that direction may be reduced.

  [0083] As shown in FIG. 8c, the pressure sensor 890 includes a pressure channel 820, which is mechanically coupled to the transducer 803 by an intervening structural element 802c. Intervening structural element 802 c couples pressure channel 820 directly to transducer 803. Therefore, the transducer 803 moves directly with the deformation of the pressure channel 820.

  [0084] The pressure to be measured may be input to the pressure sensor in any of a variety of ways. For example, the pressure channel may be routed to a channel pressure inlet / outlet on the surface of the wafer, and the pressure may be input to the pressure sensor through the channel pressure inlet / outlet. For example, the conduit pressure inlet / outlet may be formed when the pressure sensor is separated (eg, sawed) to physically remove the pressure sensor from another pressure sensor formed in the wafer. In another example, the pressure channel is routed through a lid placed on the wafer, thereby allowing the pressure inlet (e.g., rather than routing the pressure channel to the pressure inlet on the surface of the wafer) the top of the lid. You may provide in upper part. FIG. 9 illustrates one exemplary implementation in which the pressure channel is routed through the lid of the pressure sensor to the pressure inlet at the top of the lid.

  [0085] In particular, FIG. 9 is a side view of a pressure sensor 900 according to embodiments described herein. The pressure sensor 900 includes a substrate 980 (eg, a sensing wafer) and a lid 990 (eg, a capping wafer) that covers the substrate 980. The substrate 980 includes a cavity 986 that is shown as the pressure channel 920 is suspended. The pressure channel 920 connects to the ambient pressure inlet / outlet 985 via a buried pressure channel 983 and a channel 984 in the lid 990. For example, the ambient pressure inlet / outlet 985 may be made to connect to the ambient pressure to be measured. Changing the orientation of the silicon channel 984 may be accomplished by bonding two etched wafers together as shown in FIG. The purpose of indicating reorientation is to indicate that the location of the ambient pressure inlet / outlet 985 may be above the lid 990 if desired and is not limited to the location vertically above the connection to the embedded pressure conduit 983. Because. Furthermore, a plurality of pressure conduits may be constructed with a plurality of ambient doorways to create an array of pressure sensors.

  [0086] FIG. 10 is a simplified top view of a multi-cavity pressure sensor 1000 according to embodiments described herein. The pressure sensor 1000 includes a first sensing element 1088a, a second sensing element 1088b, a third sensing element 1088c, and a fourth sensing element 1088d. The first sensing element 1088a includes a first cavity 1086a and a first pressure path tube 1020a, which is suspended within the first cavity 1086a. The second sensing element 1088b includes a second cavity 1086b and a second pressure path tube 1020b, which is suspended within the second cavity 1086b. The third sensing element 1088c includes a third cavity 1086c and a third pressure path tube 1020c, which is suspended within the third cavity 1086c. The fourth sensing element 1088d includes a fourth cavity 1086d and a fourth pressure path tube 1020d, which is suspended within the fourth cavity 1086d.

[0087] In the second and third pressure passage tubes 1020b and 1020c, and in the first and fourth cavities 1086a and 1086d (except outside the first and fourth pressure passage tubes 1020a and 1020d), A pressure P1 of 1 is shown.
The second pressure in the first and fourth pressure passages 1020a and 1020d and in the second and third cavities 1086b and 1086c (except outside the second and third pressure passages 1020b and 1020c) Shown as P2. Accordingly, the first sensing element 1088a and the fourth sensing element 1088d have a similar configuration. The second sensing element 1088b and the third sensing element 1088c have a similar configuration.

  [0088] The first, second, third and fourth sensing elements 1088a-1088d are described above to compensate (eg, cancel) tilt in the X and Y direction processing, as shown in FIG. Configured as follows. For example, if the slope is in the X direction (eg, slightly more metal is deposited per unit area in a region with a relatively large Y value compared to a region with a relatively small Y value). The previously described configurations of the first, second, third, and fourth sensing elements 1088a-1088d compensate for such tilt. Similarly, if a slope exists in the Y direction (eg, if the etch is larger in a region having a relatively small X value compared to a region having a relatively large X value), the configuration described above would be To compensate for the tilt.

  [0089] The pressure sensor 1000 includes first, second, third, fourth, and fifth transport passage tubes 1092a, 1092b, 1092c, 1092d, and 1092e, each of which is for illustrative purposes. And configured as a pressure channel. Transport path tubes 1092a-1092e are configured in the plane of the wafer on which pressure sensing elements 1088a-1088d are fabricated. The plane of the wafer is defined by the X and Y axes, as shown in FIG. The first transport passage tube 1092a is connected between the first pressure passage tube 1020a and the third cavity 1086c. A portion of the first transport path tube 1092a is removed to provide an opening 1094a in the third cavity 1086c, which opens the environment within the first pressure path tube 1020a within the third cavity 1086c. To be exposed (guided) to the environment. The second transport passage tube 1092b is connected between the second pressure passage tube 1020b and the manifold 1096. A portion of second transport passage tube 1092b is removed to provide opening 1094b in manifold 1096, which exposes the environment in second pressure passage tube 1020b to the environment in manifold 1096. (invite.

  [0090] The third transport passage tube 1092c is connected between the third pressure passage tube 1020c and the manifold 1096. A portion of third transport conduit 1092c is removed to provide opening 1094c in manifold 1096, which exposes the environment in third pressure conduit 1020c to the environment in manifold 1096. (invite. The fourth transport passage tube 1092d is connected between the fourth pressure passage tube 1020d and the second cavity 1086b. A portion of the fourth transport passage tube 1092d is removed to provide an opening 1094d in the second cavity 1086b, which opens the environment of the fourth pressure passage tube 1020d in the second cavity 1086b. Expose (guide) the environment.

  [0091] The fifth transport path tube 1092e is connected between the first cavity 1086a, the fourth cavity 1086d, and the manifold 1096. A first portion of the fifth transport conduit 1092e is included in the manifold 1096. The second portion of the fifth transport path tube 1092e is contained within the first cavity 1086a. A third portion of the fifth transport path tube 1092e is contained within the fourth cavity 1086d. A portion of the first portion of the fifth transport path tube 1092e is removed to provide an opening 1094e in the manifold 1096. A portion of the second portion of the fifth transport path tube 1092e is removed to provide an opening 1094f in the first cavity 1086a. A portion of the third portion of the fifth transport path tube 1092e is removed to provide an opening 1094g in the fourth cavity 1086d. Openings 1094e, 1094f, and 0194g expose (guide) the environment in manifold 1096 to the environment in first cavity 1086a and fourth cavity 1086d. An exemplary pressure passage having an opening is described in further detail below with reference to FIG.

  [0092] Pressure measurement inlet / outlet 1098 exposes (guides) the environment of manifold 1096 to an environment outside pressure sensor 1000 (eg, the surrounding environment). For example, the first pressure P 1 may be input to the manifold 1096 through the pressure measurement inlet / outlet 1098. The first pressure P1 is from the manifold 1096, through the third transport passage tube 1092c to the third pressure passage tube 1020c, through the second transport passage tube 1092b to the second pressure passage tube 1020b, and the fifth It may be transmitted through the transport channel 1092e to the first cavity 1086a and the fourth cavity 1086d. In one example, the first pressure P1 may be a pressure to be measured and the second pressure P2 may be a reference pressure. In another example, the first pressure P1 may be a reference pressure and the second pressure P2 may be a pressure to be measured. It will be appreciated that the openings 1094a-1094g constitute respective conduit pressure outlets.

  [0093] A difference measurement is performed by comparing the first pressure P1 and the second pressure P2 (eg, subtracting the first pressure from the second pressure, or vice versa). Also good. A plurality of sensing elements are used to increase the amplitude of the signal representing the difference between the first pressure P1 and the second pressure P2 and / or to increase the signal-to-noise ratio (SNR) for the signal. It will be appreciated that each of 1086a-1086d may be included.

  [0094] The first sensing element 1088a, the second sensing element 1088b, the third sensing element 1088c, and the fourth sensing element 1088d are respectively a first transducer 1003a, a second transducer 1003b, a third A transducer 1003c and a fourth transducer 1003d are included. Sensing elements 1088a through 1088d, including their own corresponding transducers 1003a through 1003d, are shown in FIG. 10 to be configured in a grid having a first diagonal and a second diagonal. For example, the first diagonal line may include a first subset of transducers 1003a-103d (eg, first and fourth transducers 1003a and 1003d). The second diagonal may include a second subset of transducers 1003a-103d (eg, second and third transducers 1003b and 1003c). The transducers in the first subset may have a first capacitance that increases with an increase in the first pressure P1 (eg, relative to the second pressure P2). The transducers in the second subset may have a second volume that decreases with increasing first pressure P1. The transducers 1003a to 1003d may be configured to provide a differential capacitance based on the difference between the first capacitance and the second capacitance.

  [0095] FIGS. 11a-11o illustrate cross-sections of a wafer and illustrate the fabrication of a pressure sensor 1100 according to the embodiments described herein. As shown in FIG. 11 a, fabrication of the pressure sensor 1100 begins with a silicon wafer 1106. Using an oxide mask and photolithography, the trenches 1102a and 1102b are etched in the wafer 1106 in such a manner that the respective trench openings 1101a and 1101b are smaller than the respective trench bottom widths 1104a and 1104b. The oxide mask may have any suitable thickness (eg, approximately 0.5 microns). The oxide mask is stripped in a buffered oxide etch after the silicon etch, resulting in the silicon structure shown in FIG. 11a.

  [0096] Referring now to FIG. 11b, after the wafer 1106 has been etched, the wafer 1106 is relatively long enough to grow a suitable thickness of thermal oxide (eg, approximately 2.2 microns). It is placed in a high temperature (eg, 1100 ° C.) thermal oxidizer. In performing this oxidation reaction, the respective upper portions of trenches 1102a and 1102b pinch off and form respective seams 1116a and 1116b, respective sidewall oxides 1121a and 1121b, and top oxide 1114. As shown in FIG. 11b, voids 1115a and 1115b are formed within respective trenches 1102a and 1102b. The top of the trench is sealed by respective seams 1116a and 1116b, but seams 1116a and 1116b are structural weaknesses. Unless the oxidation reaction is carried out at a temperature higher than a typical quartz furnace can withstand, the seam will not melt.

  [0097] As shown in FIG. 11c, a layer of polycrystalline silicon 1130 having a suitable thickness (eg, approximately 0.5 microns thick) may be deposited to facilitate dissolution of the seams 1116a and 1116b. Good. Polycrystalline silicon 1130 can be deposited undoped using low pressure chemical vapor deposition (LPCVD) or another suitable type of deposition, and the result can be generally conformal. It will be appreciated that the seam 1116a does not necessarily need to be completely dissolved or even closed during the growth of the sidewall oxides 1121a and 1121b when additional polysilicon layers are deposited. . Polycrystalline silicon 1130 may both fill the gap and dissolve seams 1116a and 1116b.

  [0098] Referring to FIG. 11d, once the wafer undergoes a second oxidation reaction, the polycrystalline silicon 1130 turns into silicon dioxide 1131 to seal the seams 1116a and 1116b. If necessary, a chemical mechanical polishing step may be used to flatten the silicon dioxide 1131 and produce a flat surface 1132 as shown in FIG. 11e. The wafer is described as being formed from silicon for illustrative purposes, and the resulting oxide is described as silicon dioxide. It will be appreciated that the wafer may be formed from any suitable semiconductor material and the resulting oxide may be any suitable dielectric.

  [0099] As shown in FIG. 11f, a combination of photolithography and oxide etching may be used to etch vias 1140. A standard silicon contact (or another type of contact) may then be made using subsequent combinations of thin oxidation, implantation, buffered oxide etching, aluminum deposition, photolithography and metal etching. For example, the fabrication process steps described above result in metal (eg, aluminum) traces 1141.

  [0100] FIG. 11g shows an intermetal dielectric (IMD) 1142 and an adjacent silicon dioxide layer deposited conformally on trace 1141. As shown in FIG. 11h, another aluminum trace 1151 and via 1156 are formed. In this case, the interface between the aluminum is simply prepared using ion beam cleaning prior to metal deposition. FIG. 11h also shows, by way of example, a top oxide 1152 that has been planarized by chemical mechanical planarization technique (CMP) to form a top plane 1153. It will be appreciated that the top oxide 1152 need not necessarily be planarized by CMP. In fact, the top oxide 1152 does not necessarily have to be flat in any situation.

  [0101] In FIG. 11i, grown photoresist patterns 1160, 1161, and 1162 are shown. Photoresist patterns 1160, 1161, and 1162 are created to define silicon mesas, pressure sensitive elements, and silicon connection points. Note that surface 1163 is not protected by a photoresist pattern. After transferring photoresist patterns 1160, 1161, and 1162 to the underlying silicon using a combination of silicon dioxide etching and deep silicon etching, the structure shown in FIG. As shown in FIG. 11j, the uppermost portion of the pressure channel 1173 is etched away because the pressure channel 1173 is not protected by the photoresist pattern. Photoresist patterns 1160, 1161, and 1162 are slightly larger than the underlying structures (eg, pressure channel 1172 and silicon connector 1170), and they are exposed to allow typical misalignments in manufacturing. Accordingly, silicon stringers 1171 can occur on the side walls of the pressure conduits 1172 and 1173. Silicon stringer 1171 may be removed by performing a relatively short isotropic silicon etch using wet or dry chemistry. If the silicon stringers 1171 are not removed, they create undesirable asymmetries and / or undesirable signal changes due to thermal expansion coefficient (CTE) mismatch between the silicon stringers 1171 and the underlying silicon dioxide. . The result of the isotropic silicon etch should be clean sidewalls 1175 and 1176, as shown in FIG.

  [0102] As shown in FIG. 111, a conformal layer of silicon dioxide 1177 is deposited using a sputter deposition system. Silicon dioxide 1177 may be deposited, for example, using plasma enhanced chemical vapor deposition (PECVD) silane based deposition or tetraethylorthosilicate (TEOS) based deposition. By performing a subsequent anisotropic etch of silicon dioxide to remove all horizontal surfaces of silicon dioxide, the device shown in FIG. 11m is obtained. The remaining silicon dioxide sidewall 1184 covers the sides of the silicon connector 1170 and the pressure conduits 1172 and 1173.

  [0103] FIG. 11n shows a cross-section of the wafer after isotropic silicon stripping has been performed in SF6 plasma. Note that there is no silicon at the bottom 1195 of the isolation trench 1191 and the lower surface 1190 of the pressure conduits 1172 and 1173. Etch artifacts 1192 occur in the silicon substrate floor 1196 under the respective structures (ie, silicon beam 1185 and pressure conduits 1172 and 1173). A similar artifact 1183 occurs on the lower surface of the silicon beam 1185.

  [0104] As shown in FIG. 11o, the fabrication sequence may be terminated by a relatively short Primaxx® etch to remove the sidewall oxide. For example, removal of sidewall oxide results in clean silicon sidewalls 1181. Furthermore, the Primaxx® etch also etches the top oxide 1197 to an extent sufficient to expose the metal layer 1198. Exposing the metal layer 1198 is useful for providing both an adhesive pad and a seal ring for subsequent wafer scale lid bonding processes.

  [0105] FIGS. 11a-11o have been described with reference to a standard silicon wafer for purposes of illustration, but are not intended to be limiting. As will be appreciated by those skilled in the art, variations using silicon on the insulator or deposited epitaxial silicon on the oxide are within the scope of the embodiments described herein. It will be appreciated that making the pressure sensor from a standard silicon wafer may be desirable for cost reasons.

  [0106] It will be appreciated that both pressure conduits and transducers may be fabricated using the elements shown in the cross-sections described herein.

[0107] FIG. 12 depicts a pressure conduit 1200 having an opening 1294 according to the embodiments described herein. Pressure passage tube 1200 includes a first portion 1278a and a second portion 1278b. As shown in FIG. 12, the top of the second portion 1278b is etched away in the etching step. Top of the second portion 1278b is above the Y value Y _D specified along the Y axis shown in FIG. 12, is defined to be a portion of the second portion 1178B. For example, the top of the second portion 1278b used to fabricate an inertial sensor, such as an accelerometer or a gyroscope, can be modified by simply changing one of the masks used in the fabrication process. Etching may be removed as a natural part. For example, referring back to FIG. 11i, photoresist may be used to define the pattern to be etched (eg, 1160, 1161, and 1162). The pattern is intended to protect the layer underlying the pattern. In areas not protected by the pattern, etching occurs through the unprotected masking oxide into the wafer, as shown in the transition from FIG. 11i to FIG. 11j.

  [0108] Thus, when photoresist is placed on a pressure tract (eg, pressure tract 1200), the oxide under the photoresist remains untreated and the pressure tract is Roughly cut with some residue on the side (eg silicon stringer 1171). However, if the photoresist is not placed on the pressure channel (as shown for pressure channel 1173 in FIG. 11i), the top masking oxide will be etched away, but the pressure channel will remove more oxide. As such, a substantial amount of oxide remains (as shown for pressure channel 1173 in FIG. 11j). Thus, by placing the photoresist on the first portion 1278a of the pressure passage tube 1200 and not placing the photoresist on the second portion 1278b of the pressure passage tube 1200, the top of the second portion 1278b is Etching away may leave an opening 1294 in the second portion 1278b. Similarly, it will be appreciated that the etching step may etch the wafer around the pressure channel 1200. The opening 1294 is an exemplary implementation of any one or more of the openings 1094a-1094g shown in FIG. The opening 1294 may be referred to as a pressure channel inlet / outlet.

  [0109] FIG. 13 depicts a flowchart 1300 of an exemplary method for fabricating a pressure sensor according to the embodiments described herein. For purposes of illustration, the flowchart 1300 will be described with respect to the fabrication system 1400 shown in FIG. As shown in FIG. 14, the fabrication system 1400 includes cavity logic 1402, duct logic 1404, and transducer logic 1406. Further structural and operational embodiments will be apparent to those skilled in the relevant art based on the discussion regarding flowchart 1300.

  [0110] The method of flowchart 1300 begins at step 1302, as shown in FIG. In step 1302, a semiconductor substrate including a cavity is provided. In an exemplary implementation, cavity logic 1402 provides a semiconductor substrate that includes a cavity.

[0111] In step 1304, a pressure conduit having a cross section defining a void is fabricated.
The pressure passage has at least one curved portion configured to deform based on a pressure difference between the cavity pressure in the cavity and the passage pressure in the pressure passage. At least a portion of the pressure channel is suspended within the cavity. In the exemplary implementation, the conduit logic 1404 creates a pressure conduit.

  [0112] In an exemplary embodiment, step 1304 further includes embedding at least the support portion of the pressure conduit in a semiconductor substrate outside the cavity. The support portion physically supports the pressure channel. For example, the support portion may allow the pressure conduit to be suspended within the cavity.

  [0113] In step 1306, a transducer is fabricated that is coupled to a portion of the pressure conduit. The transducer has attributes that change with structural deformation of the pressure channel. In the exemplary implementation, transducer logic 1406 produces the transducer.

  [0114] In some exemplary embodiments, one or more steps 1302, 1304, and / or 1306 of flowchart 1300 may not be performed. Moreover, steps in addition to or in lieu of steps 1302, 1304, and / or 1306 may be performed. For example, in an exemplary embodiment, the pressure conduit is fabricated from a dielectric (eg, a dielectric lining) that is formed during processing of a semiconductor substrate. According to this embodiment, the method of flowchart 1300 may include forming a dielectric on a semiconductor substrate. It will be appreciated that any suitable semiconductor processing logic (eg, oxidation reaction logic) may be used to form the dielectric on the semiconductor substrate. It will further be appreciated that the pressure conduit may be made from materials other than dielectrics. For example, the pressure channel may be made of silicon rather than a dielectric, but the channel etched into the silicon can be relatively large and alignment to silicon can be a problem. .

  [0115] It will be appreciated that the fabrication system 1400 may not include all of the logic shown in FIG. For example, the fabrication system 1400 may not include one or more of the cavity logic 1402, the duct logic 1404, and / or the transducer logic 1506. Furthermore, the fabrication system 1400 may include logic in addition to or instead of the cavity logic 1402, the duct logic 1404, and / or the transducer logic 1406.

  [0116] FIG. 15 depicts a flowchart 1500 of an exemplary method for using a pressure sensor according to embodiments described herein. For purposes of illustration, flowchart 1500 will be described with respect to pressure sensor 500 shown in FIG. 5 and measurement system 1600 shown in FIG. As shown in FIG. 16, measurement system 1600 includes measurement logic 1602. Further structural and operational embodiments will be apparent to those skilled in the relevant art based on the discussion regarding flowchart 1500.

  [0117] The method of flowchart 1500 begins at step 1502, as shown in FIG. In step 1502, cavity pressure is received in a cavity included in the semiconductor substrate of the pressure sensor. In an exemplary implementation, a cavity 586 included in the semiconductor substrate 580 of the pressure sensor 500 receives the cavity pressure.

  [0118] In step 1504, the vessel pressure is received in the pressure vessel of the pressure sensor. The pressure channel has a cross section that defines a void. The pressure channel has at least one curved portion configured to deform structurally based on a pressure difference between the cavity pressure and the channel pressure. At least a portion of the pressure channel is suspended within the cavity. The pressure conduit may be made from a dielectric (e.g., a dielectric lining) formed during processing of a semiconductor substrate, but the scope of the exemplary embodiment is not limited thereto. In the exemplary implementation, pressure vessel 520 receives vessel pressure.

  [0119] At step 1506, the attributes of the transducer coupled to a portion of the pressure channel are measured. The attributes change with the structural deformation of the pressure channel. In the exemplary implementation, measurement logic 1602 measures the attributes of transducer 503.

  [0120] In an exemplary embodiment, the transducer includes a deformable capacitive structure. According to this embodiment, the attribute includes a capacity related to the capacity structure. In further accordance with this embodiment, step 1506 includes measuring a capacitance associated with the capacitive structure.

  [0121] In another exemplary embodiment, the transducer includes a piezoelectric material. According to this embodiment, the attribute includes a charge generated by the piezoelectric material. In further accordance with this embodiment, step 1506 includes measuring the charge generated by the piezoelectric material.

  [0122] In yet another exemplary embodiment, the transducer includes a piezoresistive material. According to this embodiment, the attribute includes the resistance of the piezoresistive material. In further accordance with this embodiment, step 1506 includes measuring the resistance of the piezoresistive material.

  [0123] In some exemplary embodiments, one or more of steps 1502, 1504 and / or 1506 of flowchart 1500 may not be performed. Moreover, steps may be performed in addition to or instead of steps 1502, 1504 and / or 1506.

  [0124] It will be appreciated that the measurement system 1600 may include logic in addition to or instead of the measurement logic 1602. For example, the measurement system 1600 may include a pressure sensor or a portion thereof.

[0125] The materials described herein, their respective shapes and dimensions, and their relative positions shown in the drawings are exemplary in nature and are not intended to be limiting. Modifications are envisioned as would be apparent to one of ordinary skill in the relevant art having the benefit of this disclosure.
III. Illustrative computing system implementation
[0126] The exemplary embodiments, systems, components, subcomponents, devices, methods, flowcharts described herein, including but not limited to fabrication system 1400, measurement system 1600, flowcharts 1300 and 1500, The steps and the like may be hardware (eg, hardware logic / circuit components) or any combination of hardware and software (computer program code configured to be executed on one or more processors or processing devices), And / or may be implemented in firmware. The embodiments described herein, including systems, methods / processes, and / or apparatus, may be implemented using well-known computing devices, such as the computer 1700 shown in FIG. For example, each of the steps of fabrication system 1400, measurement system 1600, flowchart 1300, and flowchart 1500 may be implemented using one or more computers 1700.

  [0127] Computer 1700 may be any commercially known communication device, processing device, and / or computer capable of performing the functions described herein, eg, International Business Machines®, Apple®, and the like. (Trademark), HP (registered trademark), Dell (registered trademark), Cray (registered trademark), Samsung (registered trademark), Nokia (registered trademark), and the like. Computer 1700 may be any type of computer including a server, desktop computer, laptop computer, tablet computer, wearable computer such as a smartwatch or head-mounted computer, a personal digital assistant, a mobile phone, and the like.

  [0128] The computer 1700 includes one or more processors (also referred to as a central processing unit or CPU), eg, a processor 1706. The processor 1706 is connected to a communication infrastructure 1702, for example, a communication bus. In some embodiments, the processor 1706 may operate multiple computing threads simultaneously. Computer 1700 also includes primary or main memory 1708, such as random access memory (RAM). Main memory 1708 has control logic 1724 (computer software) and data stored therein.

  [0129] The computer 1700 also includes one or more secondary storage devices 1710. Secondary storage devices 1710 include, for example, hard disk drives 1712 and / or removable storage devices or drives 1714, and other types of storage devices such as memory cards and memory sticks. For example, the computer 1700 may include an industry standard interface, such as a universal serial bus (USB) interface for connection to a device such as a memory stick. The removable storage drive 1714 indicates a floppy disk drive, a magnetic tape drive, a compact disk drive, an optical storage device, a tape backup, or the like.

  [0130] The removable storage drive 1714 interacts with the removable storage unit 1716. Removable storage unit 1716 includes computer software 1726 (control logic) and / or computer usable or readable storage medium 1718 having data stored therein. Removable storage unit 1716 refers to a floppy disk, magnetic tape, compact disk (CD), digital versatile disk (DVD), Blu-ray disk, optical storage disk, memory stick, memory card or any other computer data storage device. . Removable storage drive 1714 reads from and / or writes to removable storage unit 1716 in a well-known manner.

  [0131] The computer 1700 also includes input / output / display devices 1704, such as touch screens, LED and LCD displays, keyboards, pointing devices, and the like.

  [0132] The computer 1700 further includes a communication or network interface 1720. Communication interface 1720 enables computer 1700 to communicate with remote devices. For example, communication interface 1720 allows computer 1700 to communicate via a communication network or medium 1722 (representing a form of computer-usable or readable medium) such as a local area network (LAN), wide area network (WAN), the Internet, and so on. Make it possible to do. Network interface 1720 may connect to a remote site or network via a wired or wireless connection. Examples of communication interfaces 722 include a modem (eg, 3G and / or 4G communication), a network interface card (eg, an Ethernet card for Wi-Fi and / or another protocol), a communication port, a Personal Computer Memory Card International Association ( Including, but not limited to, Personal Computer Memory Card International Association (PCMCIA) cards, wired or wireless USB ports, and the like. Control logic 1728 may be transmitted to or received from computer 1700 via communication medium 1722.

  [0133] Any device or product comprising a computer-usable or readable medium having control logic (software) stored thereon is referred to herein as a computer program product or program storage device. Examples of computer program products include, but are not limited to, main memory 1708, secondary storage device 1710 (eg, hard disk drive 1712), and removable storage unit 1716. Such a computer program product having stored control logic, when executed by one or more data processing devices, causes such data processing devices to operate as described herein and represents an embodiment. . For example, such a computer program product, when executed by processor 1706, may cause processor 1706 to execute any of the steps of flowchart 1300 in FIG. 13 and / or flowchart 1500 in FIG.

  [0134] Devices with which embodiments may be implemented may include storage devices, such as storage drives, memory devices, and additional types of computer readable media. Examples of such computer readable storage media include hard disks, removable magnetic disks, removable optical disks, flash memory cards, digital video disks, random access memory (RAM), read only memory (ROM), and the like. As used herein, the terms “computer program medium” and “computer readable medium” include hard disk drive, removable magnetic disk, removable optical disk (eg, CD ROM, DVD ROM, etc.), zip disk, tape, magnetic storage. To refer generally to hard disks associated with other media such as devices, optical storage devices, MEMS-based storage devices, nanotechnology-based storage devices, and flash memory cards, digital video disks, RAM devices, ROM devices, etc. used. Such computer-readable storage media can be, for example, examples, systems, components, subcomponents, devices, methods, flowcharts, steps, such as those described herein (as described above), and / or books. A program module may be stored that includes computer program logic for implementing further embodiments described in the specification. Embodiments are directed to a computer program product comprising such logic (eg, in the form of program code, instructions, or software) stored on any computer usable medium. Such program code, when executed on one or more processors, causes the device to operate as described herein.

  [0135] Note that such computer-readable storage media is distinct from, and does not overlap (does not include) communication media. Communication media embodies computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of illustration, and not limitation, communication media includes wireless media such as acoustic, RF, infrared, and other wireless media as well as wired media. Embodiments are also directed to such communication media.

[0136] The disclosed techniques may be implemented using software, firmware and / or hardware implementations other than those described herein. Any software, firmware and hardware implementation suitable for performing the functions described herein may be used.
IV. in conclusion
[0137] While various embodiments have been described above, it should be understood that they are given by way of example only and not limitation. It will be apparent to those skilled in the relevant art that various changes in form and detail may be made therein without departing from the spirit and scope of the embodiments. Accordingly, the breadth and scope of the embodiments should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

Claims (27)

A pressure sensor, the pressure sensor comprising:
A semiconductor substrate including a first cavity;
A pressure channel tube made from a dielectric lining formed in a trench having an aspect ratio greater than 4, having a cross section defining a void, the cavity pressure in the first cavity and the pressure channel At least one curvilinear portion configured to be structurally deformed based on a pressure difference between the channel pressure in the tube and at least a first portion of the pressure channel suspended in the first cavity. With a pressure conduit,
A first transducer coupled to a first portion of the pressure conduit having a property that varies with structural deformation of the pressure conduit;
A pressure sensor. The pressure sensor of claim 1, wherein the first transducer is
A pressure sensor comprising a deformable capacitive structure configured to provide a first capacity that varies with structural deformation of the pressure conduit. 3. The pressure sensor according to claim 2, wherein the deformable capacitive structure is
A pressure sensor comprising a plurality of alternately arranged capacitor plates. 3. The pressure sensor according to claim 2, wherein the deformable capacitive structure is
A first set of capacitor plates interleaved with a second set of capacitor plates;
The first set of capacitor plates is configured to move relative to the second set of capacitor plates based on a structural deformation of the pressure conduit to change the first capacitance. A pressure sensor. The pressure sensor according to claim 4.
The deformable capacitive structure is further configured to provide a second volume that varies with structural deformation of the pressure conduit;
The deformable capacitive structure further comprises a third set of capacitor plates interleaved with a fourth set of capacitor plates;
The third set of capacitor plates is configured to move relative to the fourth set of capacitor plates based on a structural deformation of the pressure conduit to change the second capacitance. ,
The pressure sensor, wherein the change in the first capacitance is opposite to the change in the second capacitance. The pressure sensor according to claim 1.
The first transducer comprises a piezoelectric element;
The pressure sensor, wherein the piezoelectric element is configured to generate an electric charge based on a force acting on the piezoelectric element as a result of structural deformation of the pressure passage tube. The pressure sensor according to claim 1.
The first transducer comprises a piezoelectric element;
The pressure sensor according to claim 1, wherein the piezoelectric element has a resistance that changes based on a force acting on the piezoelectric element as a result of deformation of the pressure passage tube. The pressure sensor according to claim 1.
A second portion of the pressure conduit is outside the first cavity;
At least a portion of the second portion is removed to provide a passage pressure inlet / outlet that exposes a first environment in the pressure passage to a second environment outside the pressure passage. Pressure sensor. The pressure sensor according to claim 1.
A second portion of the pressure conduit is outside the first cavity;
The semiconductor substrate includes a second cavity outside the first cavity;
At least a portion of a second portion of the pressure conduit is included in the second cavity;
A portion of the second portion has an opening that exposes a first environment in the pressure channel to a second environment in the second cavity. The pressure sensor according to claim 9,
A lid, the lid comprising:
A pressure sensor comprising a hole for providing a conduit pressure inlet that exposes the first environment and the second environment to a third environment outside the pressure sensor. The pressure sensor according to claim 1.
A surrounding rectangle is defined as a rectangle having a minimum area that surrounds the first cavity in the plane of the wafer on which the pressure sensor is fabricated;
The surrounding rectangle has a first parallel side and a second parallel side perpendicular to the first parallel side, and each first parallel side has a first length. Each second parallel side has a second length that is less than or equal to the first length;
The distance between the first point where the pressure conduit is coupled to the substrate and the second point where the first transducer is coupled to the substrate is less than or equal to 1/3 of the second length. A pressure sensor characterized by being. The pressure sensor according to claim 1.
A surrounding rectangle is defined as a rectangle having a minimum area that surrounds the first cavity in the plane of the wafer on which the pressure sensor is fabricated;
The surrounding rectangle has a first parallel side and a second parallel side perpendicular to the first parallel side, and each first parallel side has a first length. Each second parallel side has a second length that is less than or equal to the first length;
The distance between a first point where the pressure channel is coupled to the substrate and a second point where the pressure channel is coupled to the first transducer is 1/3 of the second length. A pressure sensor characterized by: The pressure sensor according to claim 1.
A surrounding rectangle is defined as a rectangle having a minimum area that surrounds the first cavity in the plane of the wafer on which the pressure sensor is fabricated;
The surrounding rectangle has a first parallel side and a second parallel side perpendicular to the first parallel side, and each first parallel side has a first length. Each second parallel side has a second length that is less than or equal to the first length;
The distance between a first point at which the first transducer is coupled to the pressure conduit and a second point at which the first transducer is coupled to the substrate is 1/2 of the second length. A pressure sensor characterized by being 3 or less. The pressure sensor according to claim 1.
A pressure sensor characterized in that the maximum width of the air gap is 2 microns or less. The pressure sensor according to claim 1.
The pressure sensor, wherein at least one curved portion of the pressure passage tube includes at least one meandering portion having a meandering shape. The pressure sensor according to claim 1.
The pressure sensor, wherein at least one curved portion of the pressure passage tube includes at least one spiral portion having a spiral shape. The pressure sensor according to claim 1.
The pressure sensor, wherein the at least one curved portion of the pressure passage tube includes at least one semicircular portion having a semicircular shape. The pressure sensor according to claim 1.
The pressure sensor, wherein at least one curved portion of the pressure passage tube includes a plurality of concentric semicircular portions, and each semicircular portion has a semicircular shape. The pressure sensor according to claim 1.
A connector coupled to the pressure conduit at a first connection point and coupled to the first transducer at a second connection point;
The first connection point has a first action resulting from deformation of the pressure conduit;
The pressure sensor, wherein the connector is configured to cause the second connection point to perform a second operation, and the second operation is an amplified variation of the first operation. The pressure sensor according to claim 1.
A connector coupled to the pressure conduit at a first connection point and coupled to the first transducer at a second connection point;
The first connection point has a first action resulting from deformation of the pressure conduit;
The connector is configured to cause the second connection point to perform a second operation, and the second operation is a damped variation of the first operation. The pressure sensor according to claim 1.
The pressure sensor further comprising a connector coupled between the pressure passage tube and the first transducer, the connector having anisotropic rigidity. The pressure sensor according to claim 1.
A second pressure channel having a cross-section defining a second gap, between the cavity pressure in the second cavity contained in the semiconductor substrate and the channel pressure in the second pressure channel. A second portion having at least one curvilinear portion configured to deform based on a pressure difference of the second pressure passage, wherein at least a first portion of the second pressure passage tube is suspended in the second cavity. A second transducer coupled to a first portion of the second pressure channel, the second transducer having an attribute that varies with structural deformation of the second pressure channel. A transducer, and
The first transducer results from at least one of acceleration of the pressure passage or the pressure difference between the cavity pressure in the first cavity and the passage pressure in the first pressure passage. Configured to provide a first signal based on a change in an attribute of the first transducer;
The second transducer results from at least one of an acceleration of the pressure channel or a pressure difference between a cavity pressure in the second cavity and a channel pressure in the second pressure channel. A pressure sensor configured to provide a second signal based on a change in an attribute of the second transducer. The pressure sensor according to claim 22,
The pressure sensor provides that the difference between the first signal and the second signal provides a measure of the acceleration of the pressure sensor, and the sum of the first signal and the second signal is: A pressure sensor configured to provide a measure of pressure difference. The pressure sensor according to claim 22,
A pressure sensor, the sum of the first signal and the second signal provides a measure of the acceleration of the pressure sensor, and the difference between the first signal and the second signal is a pressure A pressure sensor configured to provide a measure of difference. The pressure sensor according to claim 22,
The pressure sensor, wherein the first cavity and the second cavity are the same. Providing a semiconductor substrate including a cavity;
Fabricating a pressure channel from a dielectric lining formed in a trench having an aspect ratio greater than 4, wherein the pressure channel has a cross-section defining a void, the pressure channel Having at least one curved portion configured to be structurally deformed based on a pressure difference between the cavity pressure in the cavity and the channel pressure in the pressure channel, wherein at least a portion of the pressure channel is the A step suspended in the cavity;
Fabricating a transducer coupled to a portion of the pressure conduit, the transducer having an attribute that varies with structural deformation of the pressure conduit;
A method comprising: Receiving the cavity pressure in a cavity contained in the semiconductor substrate of the pressure sensor;
Receiving a channel pressure into a pressure channel of the pressure sensor made from a dielectric lining formed in a trench having an aspect ratio greater than 4, wherein the pressure channel defines a void And having at least one curvilinear portion configured to deform structurally based on a pressure difference between the cavity pressure and the conduit pressure, wherein at least a portion of the pressure conduit is within the cavity Suspended by, step,
Measuring an attribute of a transducer coupled to a portion of the pressure conduit, the attribute changing with structural deformation of the pressure conduit;
A method comprising:

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